Having used a VB4 forum for a short time, my advice is "buyer beware." For example, vBulletin used to be able to display search results as threads or posts. The "posts" display showed you some text of every message in the result, to help you zero in on what you are looking for. vBulletin can no longer do the posts display. This also affects other vbulletin features that utilize search. And this is not the only problem.

So far, the only advantage I can see of the new version is it adds a CMS. The rest is worse than before.